Retaining-valve.



UNITED STATES PATENT OFFICE.

W'ILLIAM G. LAMB, OF MEXICO, MEXICO.

RETAlNlNG-VALVE.

SPECIFICATION forming part of Letters Patent No. 702,802, dated June 17,1902.

Application filed May 7,1901. Serial No. 59,143. (No modela) To all whomt may concern: v

Be it known that I, WILLIAM G. LAMB, a citizen of the United States, anda resident of the city of Mexico,-Mexico, have invented a new andImproved Automatic Retaining- Valve, of which the following is a full,clear, and exact description.

The invention relates to iiuid -pressure brakes of the YWestinghousetype; andits object is to provide a new and improved retaining-valvearranged to hold automatically the full pressure on the brakes Whilerecharging the auxiliary reservoir, so that releasing does not takeplace until the full pressure is obtained in the auxiliary reservoir andto which the retaining-valve is set.

The invention consists of novel features and parts and combinations ofthe same, as will be fully described hereinafter and then pointed out inthc claims.

A practical embodiment of the invention is represented in theaccompanying drawings, forming a part of this specication, in whichsimilar characters of reference' indicate corresponding parts in alltheviews.

Figure l is a side elevation of the improvement as applied. Fig. 2Vis aplan View of. the same. the reservoir being broken away. Fig. 8 is anenlarged transverse section of the improvement on the line 3 3 in Fig.Vl, and Fig. 4 is a sectional plan view of the same on the line 4. 4 inFig. 3.

The improved retaining-valve A illustrated is connected with the exhaustof a triple valve B and an auxiliary reservoir C. For the purposementioned a pipe D leads from the exhaust of the triple valve B to thelower end of the retaining-valve A, and a pipe F. connects the auxiliaryreservoir C with the middle portion of the retaining-valve, ashereinafter more fully explained.

The retaining-valve A is provided with a casing or valve-body,preferably made in several parts, of which the lower part F is connectedwith the pipeDand contains a valveseat F', adapted to be closed bypressure from the exhaust on a valve G, having its stem G extendingupwardly and carrying apiston G2, mounted to slide in a cylinder F2,formed on the part F, said piston G2 being pressed on by a spring H, theupper end of which rests against the under side of the piston G2, the

lower end being seated on a partition F3, dividing the cylinder Fzfromanexhaust-chamber F4, having anoutlet-port a for allowing the air toescape, as hereinafter more fully explained.

At the top of the cylinder F2 is'screwed or otherwise secured a part I,into which screws the pipe E, previously mentioned, said pipe Econnecting by a port l) with a chamber l, formed in its bottom with aneedle-pointvalve seat l2 for connecting the chamber l with the the topof the cylinder F2. The seat l2 is engaged by a needle-point J' of adiaphragm-valve J, having its diaphragm seated on a gasket K, held onthe under side of the top part L of the casing or valve-body, said toppart being screwed or otherwise secured to the top of the part l. Thebody J2 of the diaphragm-valve J is pressedon bya spring N, contained inthe top part L and resting against the under side of a plug O,adjustable in the part L, to regulate the tension of the spring N andallow of seating the valve J at the desired pressure.

The operation is as follows: When the air in the auxiliary reservoir Creaches the desired pressure to which the valve J is setsay seventypounds-then the valve J is moved upward to lift the needle-point J oithe seat I2 and allow the air to pass from the reservoir C, by way ofthe pipe E, port h, chamber I', and seat l, into the upper end of thecylinder F2 to force the piston G2 downward against the tension of thespringHand move the valve G from its seat F', so that the exhaust fromthe triple valve B can'pass through the valveseat F' into the chamberF4D and by thel port a to the outer air to release the brakes. Inapplying the brakes the pressure in the auxiliary and train pipe beingreduced, say, to ifty pounds, as the piston of the brake-cyl: inder isforced ahead the spring N forces the valve J downward against thereduced pressure in the chamber I and causes the needlepoint J to moveto its seat l2, and thereby disconnect the chamber l from the upper endof the cylinder F2. When this takes place, the exhaust from the triplevalve causes the valve G to move to its seat F and hold the pressure inthe brake-cylinder to keep the brakes applied until the auxiliaryreservoir is replenished to the full pressure-that is, to

IOO

seventy pounds-after which the above-described operation isrepeated-that is, the pressure of seventy pounds in the chamber I'causes the diaphragm-valve J'to Amove the needle-point J from its seatI2 to allow this pressure to act on the piston Gr2 and force the valve Goff its seat to allow escape of air from the exhaust of the triplevalve, as above mentioned. Thus by the arrangement described theengineer is enabled to recharge the auxiliary reservoir to the fullpressure without releasing the brakes, and this arrangement isespecially serviceable on long steep grades, as then the pressure isconsiderably reduced by leakage and it often becomes necessary torecharge the auxiliary reservoir to keep the brakes applied. Now it isevident that if the brakes have to be released from time to time on along steep downgrade while recharging the auxiliary reservoir asheretofore practiced it frequently happens that the train obtains such amomentum as to become completely out of control of the engineer. Vithmyimprovement above described the brakes remain applied while rechargingthe auxiliary reservoir.

Having thus fully described my invention, I claim as new and desire tosecure by Letters Patent- I. In a fluid-pressure brake system of theclass specified, the combination with the auxiliary reservoir andordinary triple valve, of the valve mechanism described, consisting ofthe valve-casing and pipes D and E connecting it with the triple-valveexhaust and auxiliary reservoir as shown, and having a partition withvalve-seatat I2, the valve J, its spring and adjusting device O,arranged in the upper chamber of the valve-casing the valve beingprovided with a needle-pointseating at I2 and controlling theair-passage, the second or lower valve G seating upward at a point belowthe air-outlet d, the piston Gr2 connected with the valve Gr andarranged abov'e such air-outlet, and acted on by air-pressure from aboveas shown and described.

In a fluid-pressure brake system, the combination with the auxiliaryreservoir and the triple valve, of a valve-casing having an atmosphericvent therein, a means establishing communication between thetriple-valve exhaust and the valve-casing, a valve located in thevalve-casing, said valve controlling communication between thetriple-valve exhaust and the vent in the casing, a connection betweenthe valve-casing and the auxiliary reservoir, and a second valve withinthe valvecasing, the second Valve being controlled by theauxiliary-reservoir pressure and commanding a passage in thevalve-casing through which passage the auxiliary-reservoir pressure maypass to actuate the first-named valve.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

VILLIAIWI G. LAMB. lVitnesses:

C. L. GILBERT, F. D. GORDON.

